What is it?The 24-hour electrocardiogram, often referred to as Holter, is a test that measures the electrical activity of the heart over an extended period of time, usually 24 or 48 hours, on an outpatient basis.
This exam differs from a common resting electrocardiogram, because while the resting electrocardiogram records only a few heartbeats among the more than one hundred thousand that occur throughout the day, the Holter records all of these thousands of beats, showing how your heart will react to normal daily life.
Thus, the Holter monitor provides doctors with signs of transient heart problems, that is, problems that come and go and are not apparent when a standard electrocardiogram is performed. These problems can be caused by diseases such as cardiac arrhythmias (abnormal heart rhythms) or cardiac ischemia (decreased blood flow to the heart muscles).
How is done?
The Holter ECG is a painless and simple exam, in which monitoring electrodes will be placed on the patient's chest by a technician. These electrodes will capture electrical signals from your heart and transfer them to a portable recorder. You will be asked to wear this small device for as long as your doctor prescribes.
Guidelines for exam day:
- Fasting is not necessary for the exam.
- Shower on the day of the exam (try to rub the front of your chest well to remove oil from your skin). In men, it may be necessary to shave the chest hair (trichotomy). Women should come for the exam wearing a bra. It is recommended that you wear loose-fitting shirts or blouses during the exam.
- History of allergy to alcohol or tape should be remembered when placing the electrodes.
- Medications for continuous use should not be suspended.
- Schedule the exam for a day of usual activities, such as working and driving. Avoid performing physical exercises during the exam (the specific test to evaluate the electrocardiographic tracing during physical exercise is the exercise test).
- Fill out the activity and symptoms report correctly, always writing down the respective times. Symptoms such as palpitations, dizziness, feeling faint, syncope, chest pain and shortness of breath should be noted (example: palpitations at 2:30 pm in a work meeting).